- Construction of Multiple-Substituted Chiral Cyclohexanes through Hydrogenative Desymmetrization of 2,2,5-Trisubstituted 1,3-Cyclohexanediones
-
The construction of chiral multiple-substituted cyclohexanes motifs is a challenging topic in organic synthesis. By the combination of desymmetrization and remote stereocontrol, a ruthenium-catalyzed transfer hydrogenative desymmetrization of 2,2,5-trisubstituted 1,3-cyclohexanediones has been successfully developed for the construction of chiral multiple-substituted cyclohexanes with high enantioselectivity and diastereoselectivity. When an ester group was introduced to the two-position, a hydrogenative desymmetrization/transesterification cascade occurred, affording the bicyclic lactones bearing three stereocenters, including two discrete stereocenters and one quaternary stereogenic center, with high enantioselectivity. The products are the multiple-substituted chiral cyclohexanes bearing the hydroxyl and carbonyl functional groups, which provide a new opportunity for further precise elaboration.
- Yu, Chang-Bin,Song, Bo,Chen, Mu-Wang,Shen, Hong-Qiang,Zhou, Yong-Gui
-
-
Read Online
- Enzyme-catalyzed domino reaction: Efficient construction of spirocyclic oxindole skeleton using porcine pepsin
-
Pepsin from porcine gastric mucosa was used as a sustainable and environmentally friendly biocatalyst in the domino Knoevenagel/Michael/Michael reaction for the synthesis of spirooxindole derivatives in methanol. A wide range of isatins and α,β-unsaturated ketones reacting with malononitrile provided the corresponding products in yields of up to 99% with diastereoselectivities of up to >99:1 dr. This pepsin-catalyzed domino reaction provided a novel case of enzyme catalytic promiscuity.
- He, Yan-Hong,He, Tao,Guo, Jun-Tao,Li, Rui,Xiang, Yang,Yang, Da-Cheng,Guan, Zhi
-
-
Read Online
- Boehmite - An efficient and recyclable acid-base bifunctional catalyst for aldol condensation reaction
-
In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3 · 9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α,β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.
- Reshma, P.C. Rajan,Vikneshvaran, Sekar,Velmathi, Sivan
-
-
Read Online
- Synthetic Access to gem-Difluoropropargyl Vinyl Ethers and Their Application to Propargyl Claisen Rearrangement
-
With the increasing importance of fluorine to medicinal chemistry and other areas, methods to access various fluorinated compounds are needed. Herein, we report the synthesis of difluoropropargyl vinyl ethers from ketones and aldehydes using difluoropropargyl bromide dicobalt complexes. We applied difluoropropargyl vinyl ethers to the synthesis of difluorodienone or difluoroallene under thermal conditions and trifluoro-pyran under acid-catalyzed conditions.
- Okamura, Toshitaka,Koyamada, Kenta,Kanazawa, Junichiro,Miyamoto, Kazunori,Iwabuchi, Yoshiharu,Uchiyama, Masanobu,Kanoh, Naoki
-
-
Read Online
- A bioinspired microreactor with interfacial regulation for maximizing selectivity in a catalytic reaction
-
We report a bioinspired emulsion microreactor composed of an electrical double layer to mimic the functions of cell membranes. This "artificial cell"can modulate the phase-oriented transport of reagents at the oil-liquid interface via the electrical double layer, affording a powerful tool to optimize the selectivity in a catalytic reaction. This journal is
- Han, Chenhui,Li, Xin-Hao,Waclawik, Eric R.,Xu, Haolan,Xu, Jingsan
-
-
Read Online
- Discovery of new MD2-targeted anti-inflammatory compounds for the treatment of sepsis and acute lung injury
-
Myeloid differentiation 2 (MD2) is essential to the recognition of lipopolysaccharide (LPS) and the subsequent mediation of toll-like receptor 4 (TLR4)-dependent acute inflammatory disorders including sepsis and acute lung injury. Inhibitors targeting MD2 may provide an alternative means to subdue acute inflammatory diseases. In the present study, 39 bisaryl-1,4-dien-3-one compounds with 5-carbon connection chains were designed and synthesized as MD2 inhibitors based on the analysis of the molecular docking of xanthohumol to MD2. The compound-MD2 interactions were measured by cell-free assays including bis-ANS displacement and SPR, and the active compounds were further tested for MD2 inhibition and anti-inflammatory activities in LPS-challenged macrophages. The most active compound, 1f, was shown to have remarkable protective effects against sepsis shock and pulmonary inflammation. Collectively, we present evidence that bisaryl-1,4-dien-3-one is a new lead structure for the development of anti-inflammatory agents targeting MD2.
- Chen, Gaozhi,Xiao, Bing,Chen, Lingfeng,Bai, Bin,Zhang, Yali,Xu, Zheng,Fu, Lili,Liu, Zhiguo,Li, Xiaokun,Zhao, Yunjie,Liang, Guang
-
-
Read Online
- Design, green synthesis, antioxidant activity screening, and evaluation of protective effect on cerebral ischemia reperfusion injury of novel monoenone monocarbonyl curcumin analogs
-
Antioxidants with high efficacy and low toxicity have the potential to treat cerebral ischemia reperfusion injury (CIRI). Dienone monocarbonyl curcumin analogs (DMCA) capable of overcoming the instability and pharmacokinetic defects of curcumin possess notable antioxidant activity but are found to be significantly toxic. In this study, a novel skeleton of the monoenone monocarbonyl curcumin analogue sAc possessing reduced toxicity and improved stability was designed on the basis of the DMCA skeleton. Moreover, 32 sAc analogs were obtained by applying a green, simple, and economical synthetic method. Multiple sAc analogs with an antioxidant protective effect in PC12 cells were screened using an H2O2-induced oxidative stress damage model, and quantitative evaluation of structure–activity relationship (QSAR) model with regression coefficient of R2 = 0.918921 was built through random forest algorithm (RF). Among these compounds, the optimally active compound sAc15 elicited a potent protective effect on cell growth of PC12 cells by effectively eliminating ROS generation in response to oxidative stress injury by activating the Nrf2/HO-1 antioxidant signaling pathway. In addition, sAc15 exhibited good protection against CIRI in the mice middle cerebral artery occlusion (MCAO) model. In this paper, we provide a novel class of antioxidants and a potential compound for stroke treatment.
- He, Wenfei,Wang, Jingsong,Jin, Qiling,Zhang, Jiafeng,Liu, Yugang,Jin, Zewu,Wang, Hua,Hu, Linya,Zhu, Lu,Shen, Mengya,Huang, Lili,Huang, Shengwei,Li, Wulan,Zhuge, Qichuan,Wu, Jianzhang
-
-
Read Online
- Use of a switchable-hydrophilicity solvent as both a solvent and a catalyst in aldol condensation
-
A switchable-hydrophilicity solvent, N,N-dimethylcyclohexylamine, was used as a recyclable catalyst and solvent for aldol condensation, giving >97% pure product in 94% isolated yield without the need for purification or additional solvents. CO2-triggered separation produced yields greater than conventional workup and allowed facile recycling of the amine.
- Poole, Hailey,Gauthier, Jeremy,Vanderveen, Jesse R.,Jessop, Philip G.,Lee, Roland
-
-
Read Online
- Piperlongumine derivative as well as preparation method and application thereof
-
The invention discloses a Piperlongumine derivative as well as a preparation method and application thereof. The Piperlongumine derivative has the following structure: the Piperlongumine derivative provided by the invention contains a plurality of Michael addition receptor units, and the novel structure improves the electrophilicity, so that the Piperlongumine derivative has good protein targetingpotential, and the Piperlongumine derivative has a good inhibition effect on thioredoxin reductase; in an antitumor bioactive in-vitro screening experiment, the derivative also has a certain inhibition effect on the growth of tumor cells, and meanwhile, the derivative has an effect of promoting the generation of active oxygen in A549 human lung cancer cells.
- -
-
Paragraph 0033; 0040; 0064-0067
(2021/01/28)
-
- 8-Hydroxyquinolin-2(1H)-one analogues as potential β2-agonists: Design, synthesis and activity study
-
β2-Agonists that bind to plasmalemmal β2-adrenoceptors causing cAMP accumulation are widely used as bronchodilators in chronic respiratory diseases. Here, we designed and synthesized a group of 8-hydroxyquinolin-2(1H)-one analogues and studied their β2-agonistic activities with a cellular cAMP assay. Compounds B05 and C08 were identified as potent (EC50 2-agonists among the compounds tested. They behaved as partial β2-agonists in non-overexpressed HEK293 cells, and possessed rapid smooth muscle relaxant actions and long duration of action in isolated guinea pig tracheal strip preparations. In summary, B05 and C08 are β2-agonists with potential applicability in chronic respiratory diseases.
- Xing, Gang,Zhi, Zhengxing,Yi, Ce,Zou, Jitian,Jing, Xuefeng,Yiu-Ho Woo, Anthony,Lin, Bin,Pan, Li,Zhang, Yuyang,Cheng, Maosheng
-
-
- Selective Cross-Dehydrogenative C(sp3)-H Arylation with Arenes
-
Selective C(sp3)-C(sp2) bond construction is of central interest in chemical synthesis. Despite the success of classic cross-coupling reactions, the cross-dehydrogenative coupling between inert C(sp3)-H and C(sp2)-H bonds represents an attractive alternative toward new C(sp3)-C(sp2) bonds. Herein, we establish a selective inter-and intramolecular C(sp3)-H arylation of alcohols with nondirected arenes that thereby provides a general pathway to access a wide range of β-arylated alcohols, including tetrahydronaphthalen-2-ols and benzopyran-3-ols, with high to excellent chemo-and regioselectivity.
- Hao, Hong-Yan,Mao, Yang-Jie,Xu, Zhen-Yuan,Lou, Shao-Jie,Xu, Dan-Qian
-
supporting information
p. 2396 - 2402
(2020/03/13)
-
- Stereodivergent Pd/Cu Catalysis for the Dynamic Kinetic Asymmetric Transformation of Racemic Unsymmetrical 1,3-Disubstituted Allyl Acetates
-
A stereodivergent Pd/Cu catalyst system has been developed for the unprecedented dynamic kinetic asymmetric transformation (DyKAT) of racemic unsymmetrical 1,3-disubstituted allylic acetates with prochiral aldimine esters. A series of α,α-disubstituted α-amino acids bearing vicinal stereocenters were easily prepared with excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >20:1 dr). Moreover, all four stereoisomers of the product can be readily obtained simply by switching the configurations of the two chiral metal catalysts. Furthermore, the present work highlights the power of synergistic Pd/Cu catalysis consisting of two common bidentate chiral ligands for stereodivergent synthesis.
- He, Rui,Huo, Xiaohong,Zhao, Ling,Wang, Feijun,Jiang, Liyin,Liao, Jian,Zhang, Wanbin
-
supporting information
p. 8097 - 8103
(2020/05/22)
-
- Sequential Two-Step Stereoselective Amination of Allylic Alcohols through the Combination of Laccases and Amine Transaminases
-
A sequential two-step chemoenzymatic methodology for the stereoselective synthesis of (3E)-4-(het)arylbut-3-en-2-amines in a highly selective manner and under mild reaction conditions is described. The approach consists of oxidation of the corresponding racemic alcohol precursors by the use of a catalytic system made up of the laccase from Trametes versicolor and the oxy-radical TEMPO, followed by the asymmetric reductive bio-transamination of the corresponding ketone intermediates. Optimisation of the oxidation reaction, exhaustive amine transaminase screening for the bio-transaminations and the compatibility of the two enzymatic reactions were studied in depth in search of a design of a compatible sequential cascade. This synthetic strategy was successful and the combinations of enzymes displayed a broad substrate scope, with 16 chiral amines being obtained in moderate to good isolated yields (29–75 %) and with excellent enantiomeric excess values (94 to >99 %). Interestingly, both amine enantiomers can be achieved, depending on the selectivity of the amine transaminase employed in the system.
- Albarrán-Velo, Jesús,Lavandera, Iván,Gotor-Fernández, Vicente
-
p. 200 - 211
(2019/12/03)
-
- One-pot two-step chemoenzymatic deracemization of allylic alcohols using laccases and alcohol dehydrogenases
-
A series of enantioenriched (hetero)aromatic secondary allylic alcohols has been synthesized through deracemization of the corresponding racemic mixtures combining a non-selective chemoenzymatic oxidation (laccase from Trametes versicolor and oxy-radical TEMPO) and a stereoselective biocatalyzed reduction (lyophilized cells of E. coli overexpressing an alcohol dehydrogenase, ADH). Both steps were performed in aqueous medium under very mild reaction conditions. After optimization, a sequential one-pot two-step protocol was set up, obtaining the corresponding chiral alcohols in moderate to high conversions (48–95%) and enantiomeric excess (65->99% ee). Depending on the ADH stereopreference, both antipodes from these valuable chiral synthons could be prepared, even at preparative scale (119?178 mg), in a straightforward manner.
- Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
-
-
- Iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes
-
The first iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes was achieved. The reaction tolerates a wide range of functionalities. Furthermore, this protocol was found to be applicable to the oxidative transformation of allylic acetates. The proposed mechanism involves an oxygen transfer from solvent water to the carbonyl products.
- Chen, Weifeng,Jiang, Kezhi,Xue, Yuntian,Yan, Yaolong,Yang, Lei
-
p. 14720 - 14724
(2020/04/27)
-
- Nucleophilic Organic Base DABCO-Mediated Chemospecific Meinwald Rearrangement of Terminal Epoxides into Methyl Ketones
-
Nucleophilic organic base DABCO (1,4-diazabicyclo[2.2.2]octane)-mediated Meinwald rearrangement of various epoxides was investigated. 2-Aryl-, alkenyl-, and alkynylepoxides generate the corresponding methyl ketones chemospecifically in good to excellent yields. The current DABCO-mediated Meinwald rearrangement of epoxides features readily accessible starting materials, a wide substrate scope, a transition-metal- and acid-free environment, and chemospecificity in the isomerization of epoxides.
- Li, Siqi,Shi, Yi,Li, Pingfan,Xu, Jiaxi
-
p. 4443 - 4450
(2019/04/30)
-
- Dehydrozingerone Inspired Discovery of Potential Broad-Spectrum Fungicidal Agents as Ergosterol Biosynthesis Inhibitors
-
A series of dehydrozingerone derivatives were synthesized, and their fungicidal activities and action mechanism against Colletotrichum musae were evaluated. The bioassay result showed that most compounds exhibited excellent fungicidal activity in vitro at 50 μg mL-1. Compounds 13, 16, 18, 19, and 27 exhibited broad-spectrum fungicidal activity; especially, compounds 19 and 27 were found to have more potent fungicidal activity than azoxystrobin. The EC50 values of compounds 19 and 27 against Rhizoctonia solani were 0.943 and 0.161 μg mL-1 respectively. Moreover, compound 27 exhibited significant in vitro bactericidal activity against Xanthomonas oryzae pv. oryzae, with an EC50 value of 11.386 μg mL-1, and its curative effect (49.64%) and protection effect (51.74%) on rice bacterial blight disease was equivalent to that of zhongshengmycin (42.90%, 40.80% respectively). Compound 27 could also effectively control gray mold (87.10%, 200 μg mL-1) and rice sheath blight (100%, 200 μg mL-1 82.89%, 100 μg mL-1) in vivo. Preliminary action mechanism study showed that compound 27 mainly acted on the cell membrane and significantly inhibited ergosterol biosynthesis in Colletotrichum musae.
- Song, Xiangmin,Zhu, Xinyue,Li, Ting,Liang, Cai,Zhang, Meng,Shao, Yu,Tao, Jun,Sun, Ranfeng
-
p. 11354 - 11363
(2019/10/16)
-
- Dehydrozingerone derivative and preparation method and application thereof
-
The invention provides a dehydrozingerone derivative as shown in the description. R-R are each independently selected from hydrogen or halogen or a nitro group or an alkyl group or a substitutedalkoxy group or an alkoxy group or a hydroxyl group; the substituent in the substituted alkoxy group is selected from one or multiple of halogen, a nitro group and a hydroxyl group; R and R areeach independently selected from hydrogen or halogen or nitrogen-containing heterocycle; R is selected from an alkyl group or an alkoxy group or a substituted alkoxy group; the substituent in thesubstituted alkyl group is selected from one or multiple of halogen, a nitro group and a hydroxyl group; X is selected from a hetero atom or a hydroxylamine group. The dehydrozingerone derivative hasbroad-spectrum activity against plant pathogenic fungi and bacteria, and has certain nematicidal activity, and is a lead compound with the broad biological activity.
- -
-
Paragraph 0084-0087; 0088; 0095
(2019/11/20)
-
- Containing nitro of curcumin derivatives and its preparation method and application
-
The invention discloses a curcumin derivative as shown in formula (I) as well as a preparation method and application of the curcumin derivative. The invention provides a novel curcumin derivative, and the derivative has an anti-inflammatory activity and can be used as an active ingredient in anti-inflammatory drugs or anti-inflammatory pharmaceutical compositions. Furthermore, the invention also provides a preparation method of the curcumin derivative as shown in formula (I). The invention belongs to the technical field of chemical drugs; the curcumin derivative is better than curcumin in stability, and the curcumin derivative is low in preparation cost and good in realizability.
- -
-
Paragraph 0115; 0116; 0117
(2017/08/25)
-
- Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer
-
The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biological evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Additionally, 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer.
- Ai, Yong,Zhu, Bin,Ren, Caiping,Kang, Fenghua,Li, Jinlong,Huang, Zhangjian,Lai, Yisheng,Peng, Sixun,Ding, Ke,Tian, Jide,Zhang, Yihua
-
p. 1747 - 1760
(2016/03/25)
-
- Iridium(I) N-Heterocyclic Carbene (NHC)/Phosphine Catalysts for Mild and Chemoselective Hydrogenation Processes
-
The directed chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity. The directed, chemoselective hydrogenation of olefins has been established by using iridium(I) catalysts, which feature a tuned NHC/phosphine ligand combination. This selective reduction process has been demonstrated in a wide array of solvents, including more environmentally acceptable media, also allowing further refinement of hydrogenation selectivity.
- Kerr, William J.,Mudd, Richard J.,Brown, Jack A.
-
supporting information
p. 4738 - 4742
(2016/04/05)
-
- Organoselenium-catalyzed baeyer-villiger oxidation of α,β-unsaturated ketones by hydrogen peroxide to access vinyl esters
-
By carefully screening the organoselenium pre-catalysts and optimizing the reaction conditions, simple dibenzyl diselenide was found to be the best pre-catalyst for Baeyer-Villiger oxidation of (E)-α,β-unsaturated ketones with the green oxidant hydrogen peroxide at room temperature. The organoselenium catalyst used in this reaction could be recycled and reused several times. This new method was suitable not only for methyl unsaturated ketones, but also for alkyl and aryl unsaturated ketones. Therefore, it provided a direct, mild, practical, highly functional group-tolerant process for the chemoselective preparation of the versatile (E)-vinyl esters from the readily available (E)-α,β-unsaturated ketones. A possible mechanism was also proposed to rationalize the activity of the organoselenium catalyst in the presence of hydrogen peroxide in this Baeyer-Villiger oxidation reaction.
- Zhang, Xu,Ye, Jianqing,Yu, Lei,Shi, Xinkang,Zhang, Ming,Xu, Qing,Lautens, Mark
-
supporting information
p. 955 - 960
(2015/03/30)
-
- Synthesis of Polysubstituted Pyridines via a One-Pot Metal-Free Strategy
-
An efficient strategy for the one-pot synthesis of polysubstituted pyridines via a cascade reaction from aldehydes, phosphorus ylides, and propargyl azide is reported. The reaction sequence involves a Wittig reaction, a Staudinger reaction, an aza-Wittig reaction, a 6π-3-azatriene electrocyclization, and a 1,3-H shift. This protocol provides quick access to the polysubstituted pyridines from readily available substrates in good to excellent yields.
- Wei, Hongbo,Li, Yun,Xiao, Ke,Cheng, Bin,Wang, Huifei,Hu, Lin,Zhai, Hongbin
-
supporting information
p. 5974 - 5977
(2016/01/09)
-
- Iridium(I)-catalyzed regioselective C-H activation and hydrogen-isotope exchange of non-aromatic unsaturated functionality
-
Isotopic labelling is a key technology of increasing importance for the investigation of new C-H activation and functionalization techniques, as well as in the construction of labelled molecules for use within both organic synthesis and drug discovery. Herein, we report for the first time selective iridium-catalyzed C-H activation and hydrogen-isotope exchange at the β-position of unsaturated organic compounds. The use of our highly active [Ir(cod)(IMes)(PPh3)][PF6] (cod = 1, 5-cyclooctadiene) catalyst, under mild reaction conditions, allows the regioselective β-activation and labelling of a range of α, β-unsaturated compounds with differing steric and electronic properties. This new process delivers high levels of isotope incorporation over short reaction times by using low levels of catalyst loading.
- Kerr, William J.,Mudd, Richard J.,Paterson, Laura C.,Brown, Jack A.
-
supporting information
p. 14604 - 14607
(2015/03/04)
-
- Highly enantioselective biomimetic intramolecular dehydration: Kinetic resolution of β-hydroxy ketones catalyzed by β-turn tetrapeptides
-
Racemic β-hydroxy ketones were kinetically resoluted into the enantiopure isomers and (E)-α,β-unsaturated ketones using catalytic asymmetric intramolecular dehydration for the first time. Synthetic tetrapeptides were used to imitate fatty acid dehydratase
- Du, Zhi-Xue,Zhang, Li-Yuan,Fan, Xin-Yuan,Wu, Feng-Chun,Da, Chao-Shan
-
supporting information
p. 2828 - 2832
(2013/06/05)
-
- Palladium-catalyzed conjugate addition of arylsulfonyl hydrazides to α,β-unsaturated ketones
-
A palladium-catalyzed desulfitative-denitrogenative conjugate addition of arylsulfonyl hydrazides to α,β-unsaturated ketones is described. The reaction showed very good selectivity and tolerated a wide range of functionalities under an atmosphere of oxygen with or without the aid of a metal co-oxidant. The Royal Society of Chemistry 2013.
- Chen, Wen,Chen, Hui,Xiao, Fuhong,Deng, Guo-Jun
-
supporting information
p. 4295 - 4298
(2013/08/23)
-
- Cu(OAc)2/TFA-promoted formal [3 + 3] cycloaddition/oxidation of enamines and enones for synthesis of multisubstituted aromatic amines
-
New strategies for the oxidative cycloaddition of enones with enamines are developed. These cycloaddition reactions directly afford substituted aromatic amines, which are important in organic chemistry, in moderate to good yield. Cu(OAc)2/TFA is shown to be essential to achieve high reaction efficiency.
- Li, Liang,Zhao, Mi-Na,Ren, Zhi-Hui,Li, Jian-Li,Guan, Zheng-Hui
-
supporting information; experimental part
p. 3506 - 3509
(2012/08/08)
-
- Anomalous Z-isomer content in Wittig reaction products from keto-stabilised ylides with ortho-heteroatom substituted benzaldehydes
-
Wittig reaction products of keto-stabilised ylides with ortho-substituted benzaldehydes are found to show significantly higher than expected Z-alkene content (up to 50%) compared to analogous reactions of the same ylides with benzaldehyde itself. A cooperative effect is seen whereby the unusual Z-content is further augmented if the ylide bears greater steric bulk in the α′-position. These results are consistent with our previous observations on reactions of all ylide types with aldehydes bearing a β-heteroatom. Significantly, the cooperative effect, previously seen only with semi-stabilised ylides, has now been extended to stabilised ylides. Both the anomalous increase in Z-content and the cooperative effect can be rationalised within the [2+2] cycloaddition mechanism of the Wittig reaction.
- Byrne, Peter A.,Higham, Lee J.,McGovern, Pádraic,Gilheany, Declan G.
-
supporting information
p. 6701 - 6704
(2013/01/15)
-
- QUINAZOLIN-OXIME DERIVATIVES AS HSP90 INHIBITORS
-
Compounds of general formula (I); or a stereoisomers, tautomers, pharmaceutically acceptable salts, or prodrugs thereof, wherein R1, R2, R3, R4, R5, R6, R8 and R9 are as defined herein, are useful for the treatment of diseases and conditions which are mediated by excessive or inappropriate Hsp90 activity such as cancers, viral infection and inflammatory diseases or conditions.
- -
-
Page/Page column 10
(2011/06/10)
-
- High-pressure access to the Δ9-cis - And Δ9-trans-tetrahydrocannabinols family
-
Diels-Alder reactions of a range of 1-(alkoxy/alkyl-substituted phenyl)buta-1,3-dienes with methyl vinyl ketone and methyl acrylate carried out in ethanol as the reaction medium under 9 kbar pressure were investigated. The use of high pressure as the activating method of the Diels-Alder reactions allows the efficient and endodiastereoselective generation of a series of cis-cyclohexenyl-benzene cycloadducts, which are selectively converted into their trans-epimers. The cis-cyclohexenyl-benzenes and trans-cyclohexenyl- benzenes produced are useful precursors for accessing substituted privileged cis-6a,7,8,10a-tetrahydro-6H-benzo[c]chromene and trans-6a,7,8,10a-tetrahydro- 6H-benzo[c]chromene skeletons. The total syntheses of Δ9-cis- tetrahydrocannabinol (THC) and Δ9-trans-THC, through the use of selected Diels-Alder adducts, are described. Finally, a route for obtaining Δ9-trans-THC in both enantiomeric pure forms based on the (S)-(-)-1-amino-2-(methoxymethyl)pyrrolidine (SAMP)-hydrazone method is also reported.
- Minuti, Lucio,Ballerini, Eleonora
-
supporting information; scheme or table
p. 5392 - 5403
(2011/08/06)
-
- Rhodium(III)-catalyzed synthesis of pyridines from α,β- unsaturated ketoximes and internal alkynes
-
A method for the synthesis of highly substituted pyri-dines from ,-unsaturated oximes and internal alkynes has been developed using [Cp*RhCl2]2-CsOPiv as the catalyst system. The present transformation is carried out by a redox-neutral sequence of vinylic C-H rhodation, alkyne insertion, and C-N bond formation of the putative vinyl rhodium intermediate with the oxime nitrogen, where the N-O bond of oxime derivatives could work as an internal oxidant to maintain the catalytic cycle. Georg Thieme Verlag Stuttgart · New York.
- Too, Pei Chui,Noji, Toshiharu,Lim, Ying Jie,Li, Xingwei,Chiba, Shunsuke
-
supporting information; experimental part
p. 2789 - 2794
(2012/01/11)
-
- High-pressure diels-alder cycloadditions between benzylideneacetones and 1,3-Butadienes: Application to the synthesis of (R,R)-(-)- and (S,S)-(+)-Δ8-tetrahydrocannabinol
-
High-pressure Diels-Alder reactions of various alkoxy/alkyl-substituted benzylideneacetones with methyl-1,3-butadienes are reported. Activation by high pressure (8-11 kbar) in combination with the mild Lewis acid HfCl 42THF allows these reactions to efficiently and regioselectively produce a series of ortho-substituted cyclohexenyl-benzene cycloadducts, that are useful precursors for the expeditious construction of the privileged 6,6-dimethyltetrahydro-6H-benzo[c]chromene skeleton. Application to the synthesis of Δ8-trans-THC in both enantiomeric pure forms is based on the successful resolution of selected cycloadduct by the SAMP-hydrazone method.
- Ballerini, Eleonora,Minuti, Lucio,Piermatti, Oriana
-
supporting information; experimental part
p. 4251 - 4260
(2010/09/05)
-
- Regioselective heck vinylation of electron-rich olefins with vinyl halides: Is the neutral pathway in operation?
-
Highly regioselective vinylation of electron-rich olefins by bromo- as well as chlorostyrenes is effected by palladium catalysis with either mono- or bidentate phosphines in a molecular solvent, with no need for halide scavengers, ionic liquids, or ionic additives. The use of the hemilabile 1,3-bis(diphenylphosphino)propane monoxide (dpppO) as a ligand led to faster reactions of more challenging 2-substituted vinyl ethers and reduced Pd loadings. In contrast to the related arylation reaction, evidence suggests that the vinylation may proceed via the neutral Heck mechanism.
- McConville, Matthew,Saidi, Ourida,Blacker, John,Xiao, Jianliang
-
supporting information; experimental part
p. 2692 - 2698
(2009/08/15)
-
- Lipase-catalysed decarboxylative aldol reaction and decarboxylative Knoevenagel reaction
-
Acrylic resin immobilized Candida antarctica lipase B (CAL-B) is able to catalyse decarboxylative aldol reaction and decarboxylative Knoevenagel reaction with good to excellent yields.
- Feng, Xing-Wen,Li, Chao,Wang, Na,Li, Kun,Zhang, Wei-Wei,Wang, Zao,Yu, Xiao-Qi
-
scheme or table
p. 1933 - 1936
(2010/06/15)
-
- HETEROCYCLIC COMPOUNDS USEFUL AS ANABOLIC AGENTS FOR LIVESTOCK ANIMALS
-
Compounds of formula (I) and pharmaceutically acceptable salts thereof are agonists at the beta-2 adrenoceptor. They are useful as feed additives for livestock animals.
- -
-
Page/Page column 82
(2008/06/13)
-
- Enantiomerically pure allylic alcohols: preparation by Candida parapsilosis ATCC 7330 mediated deracemisation
-
Biocatalytic deracemisation of racemic allylic alcohols by whole cells of Candida parapsilosis ATCC 7330 resulted in the formation of the (R)-enantiomers in high enantiomeric excesses (up to >99%) and isolated yields (up to 79%).
- Titu, Devamani,Chadha, Anju
-
p. 1698 - 1701
(2008/12/20)
-
- Gallium(III) chloride catalyzed stereoselective synthesis of E-configured α,β-unsaturated ketones
-
A simple and highly stereoselective method has been developed for the synthesis of E-configured α,β-unsaturated ketones using gallium(III) chloride as a novel catalyst. This new procedure offers significant advantages such as high conversions, short reac-tion times and enhanced E-selectivity together with mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Yadav,Reddy, B. V. Subba,Gupta, Manoj K.,Dash, Uttam,Pandey, Sushil K.
-
p. 809 - 811
(2007/12/26)
-
- Cycloaddition of 1-aryl-3-trimethylsiloxy-1,3-butadienes in the synthesis of natural quinone analogs
-
7-Hydroxy-5-(2-methoxyphenyl)-2-methyl-6-R-1,4-naphthoquinones, 8-hydroxy-1-(2-methoxyphenyl)-3-oxo-1,2,3,4-tetrahydro-9,10-anthraquinone, and 2-ethoxycarbonyl-8-hydroxy-1-(2-methoxyphenyl)-3-trimethylsiloxy-1,1a,4,4a-tetrahydro-9,10-anthraquinone were sy
- Nechepurenko,Shul'ts,Tolstikov
-
p. 1276 - 1283
(2007/10/03)
-
- Unsaturated oxime ethers and their use as fungicides and insecticides
-
Compounds with fungicidal and insecticidal properties having formula wherein X is N or CH; Y is O, S or NR6; A is independently hydrogen, halo, cyano, (C1-C12)alkyl, or (C1-C12)alkoxy; R1and R6is independently hydrogen or (C1-C4)alkyl; R2is independently hydrogen, (C1-C12)alkyl, halo(C1-C12)alkyl, (C3-C7)cycloalkyl, (C2-C8)alkenyl, halo(C2-C8)alkenyl, (C2-C8)alkynyl, halo(C2-C8)alkynyl, aryl, aralkyl, heterocyclic, or heterocyclic(C1-C4)alkyl; R3is independently hydrogen or (C1-C4)alkyl; R4and R5is independently hydrogen, (C1-C4)alkyl, aryl, aralkyl, aryl(C2-C8)alkenyl, aryl(C2-C8)alkynyl, heterocyclic, or heterocyclic(C1-C4)alkyl wherein if one of R4and R5is hydrogen or (C1-C4)alkyl than the other of R4and R5is other than hydrogen or (C1-C4)alkyl, and its enantiomers and stereoisomers and agronomically acceptable salts.
- -
-
-
- Photo-induced intramolecular arene-olefin meta-cycloaddition of 5-phenyl-fluorinated-pent-1-enes
-
A series of fluorinated angular and linear triquinanes and their aza-analogues have been synthesized by photo-induced intramolecular meta-cycloaddition of 5-phenyl-fluorinated-pent-1-enes.
- Guo, Xiao-Chuan,Chen, Qing-Yun
-
p. 149 - 156
(2007/10/03)
-
- Clean three-step synthesis of 4,5-dihydro-1H-pyrazoles starting from alcohols using polymer supported reagents
-
Nafion-TMS mediated Mukaiyama aldol reaction of silyl enol ethers with aldehydes, obtained from mild oxidation of alcohols with polymer supported perruthenate (PSP), yielded α,β-unsaturated ketones, which upon treatment with hydrazines allowed the clean synthesis of 4,5-dihydro-1H-pyrazoles.
- Haunert, Frank,Bolli, Martin H.,Hinzen, Berthold,Ley, Steven V.
-
p. 2235 - 2237
(2007/10/03)
-
- Nickel- and Palladium-Catalyzed Aldol-Type Condensation by Enol Esters
-
PdCl2(PhCN)2-SnCl2, bis(1,5-cyclooctadiene)nickel(0) /PPh3-Zn, NiBr2(PPh3)2-Zn, or Pd-(OAc)2/PPh3-Zn catalytic systems induced aldol-type condensation of isopropenyl acetate with aldehydes to produce 4-substituted (E)-3-buten-2-ones.PdCl2(PhCN)2-SnCl2 was utilized in the aldol-type reaction with any arenecarbaldehyde, bearing either an electron-donating group or an electron-withdrawing group, at 50 deg C in acetonitrile.Catalytic systems using zinc, in particular Ni(cod)2/PPh3-Zn, exhibited some high chemoselectivities at 60 deg C in dioxane: (1) an aldehyde only reacted in the presence of an internal ester or ketone, (2) olefinic aldehydes only reacted in the presence of saturated aliphatic aldehydes, (3) reactivity in the condensation with substituted benzaldehydes is the inverse of that in usual nucleophilic addition to carbonyl compound, and (4) 2-methoxybenzaldehyde only reacted in the presence of 4-methoxybenzaldehyde.Using PdCl2(PhCN)2-SnCl2, Ni(cod)2/PPh3-Zn, or Pd(OAc)2/PPh3-Zn, cyclic enol ester, namely 5-methyl-2(3H)-furanone also caused aldol-type reaction with carbonyl compounds.The reaction with Ni(cod)2/PPh3-Zn or Pd(OAc)2/PPh3-Zn at 60 deg C in dioxane selectively produced 5-substituted 4-acetyl-2(5H)-furanones via dehydrogenation of γ-substituted β-acetyl-γ-butyrolactones.
- Masuyama, Yoshiro,Sakai, Tatsuya,Kato, Takeshi,Kurusu, Yasuhiko
-
p. 2265 - 2272
(2007/10/02)
-
- Palladium-catalyzed aldol-type condensation by enol esters with SnCl2
-
Using PdCl2(PhCN)2-SnCl2, enol esters caused aldol-type condensation with aldehydes at 50°C in acetonitrile to produce (E)-α,β-unsaturated carbonyl compounds. Cyclic enol ester such as α-angelicalactone also reacted with aldehydes under the same conditions to afford γ-substituted β-acetyle-γ-butyrolactones and/or 5-substituted 4-acetyl-2(5H)-furanones.
- Masuyama, Yoshiro,Sakai, Tatsuya,Kurusu, Yasuhiko
-
p. 653 - 656
(2007/10/02)
-
- Synthesis and Antimalarial Properties of 1-Imino Derivatives of 7-Chloro-3-substituted-3,4-dihydro-1,9(2H,10H)-acridinediones and Related Structures
-
To improve upon the activity and properties of the 3-aryl-7-chloro-3,4-dihydro-1,9(2H,10H)-acridinediones, a variety of 1-imino derivatives (3) were prepared and shown to be highly active antimalarial agents in both rodents and primates.Among structural modifications prepared, including N10-alkyl and C2-substituted analogs, removal of the C9 oxygen, and introduction of an imino side chain at C9, the imines of the N10-H acridinediones were the most active compounds obtained.The imino derivative of7-chloro-3-(2,4-dichlorophenyl)-3,4-dihydro-1,9(2H,10H)-acridinedione (9aa) proved to be highly active in advanced studies in primates.
- Kesten, Stephen J.,Degnan, Margaret J.,Hung, Jocelyn,McNamara, Dennis J.,Ortwine, Daniel F.,et al.
-
p. 3429 - 3447
(2007/10/02)
-
- Substituted chromans
-
The invention relates to chroman derivatives of the general formula STR1 wherein R1 is hydrogen, lower alkyl, substituted phenyl, phenyl, phenyl-lower alkyl, substituted phenyl-lower alkyl or lower alkyl-amino-lower alkyl; R2 is STR2 R3, R4, R5 and R6 each is independently selected from hydrogen, hydroxy, amino, -o-acyl, -o-lower alkyl; STR3 halogen, lower alkyl, or halo substituted lower alkyl; and salts and hydrates thereof. These compounds are useful as anti-inflammatory agents; for inhibition of blood platelet aggregation, as antiallergy and as antihypertensive agents.
- -
-
-